System and method for controlling remote devices

ABSTRACT

A system and method for controlling remote devices utilizing a radio frequency identification (RFID) tag device having a control circuit adapted to render the tag device, and associated objects, permanently inoperable in response to radio-frequency control signals. The control circuit is configured to receive the control signals that can include an enable signal, and in response thereto enable an associated object, such as a weapon; and in response to a disable signal, to disable the tag itself, or, if desired, to disable the associated weapon or both the device and the weapon. Permanent disabling of the tag can be accomplished by several methods, including, but not limited to, fusing a fusable link, breaking an electrically conductive path, permanently altering the modulation or backscattering characteristics of the antenna circuit, and permanently erasing an associated memory. In this manner, tags in the possession of unauthorized employees can be remotely disabled, and weapons lost on a battlefield can be easily tracked and enabled or disabled automatically or at will.

STATEMENT REGARDING FEDERALLY-SPONSORED RESEARCH OR DEVELOPMENT

[0001] This invention was made with Government support under ContractDE-AC0676RLO1830 awarded by the U.S. Department of Energy. TheGovernment has certain rights in the invention.

TECHNICAL FIELD

[0002] The present invention pertains to radio frequency identification(RFID) devices, and, more particularly, to an RFID system that rendersRFID tags, and associated objects, inoperable.

BACKGROUND INFORMATION

[0003] Remote communication utilizing wireless equipment typicallyrelies on radio frequency (RF) technology. One application of RFtechnology is in locating, identifying, and tracking objects, such asanimals, inventory, and vehicles. RF identification (RFID) systems havebeen developed that facilitate monitoring of remote objects.

[0004] As shown in FIG. 1, a basic RFID system 10 includes twocomponents: an interrogator or reader 12, and a transponder (commonlycalled an RF tag) 14. The interrogator 12 and RF tag 14 includerespective antennas 16, 18. In operation, the interrogator 12 transmitsthrough its antenna 16 a radio frequency interrogation signal 20 to theantenna 18 of the RF tag 14. In response to receiving the interrogationsignal 20, the RF tag 14 produces a modulated response signal 22 that istransmitted back to the interrogator 12 through the tag antenna 18 by aprocess known as continuous wave backscatter.

[0005] The substantial advantage of RFID systems is the non-contact,non-line-of-sight capability of the technology. The interrogator 12emits the interrogation signal 20 with a range from one inch to onehundred feet or more, depending upon its power output and the radiofrequency used. Tags can be read through a variety of substances such asodor, fog, ice, paint, dirt, and other visually and environmentallychallenging conditions where bar codes or other optically-readtechnologies would be useless. RF tags can also be read at high speeds,in most cases responding in less than one hundred milliseconds.

[0006] RF tags are divided into three main categories: Beam-poweredpassive tags, battery-powered semi-passive tags, and active tags. Eachoperates in different ways.

[0007] The beam-powered RFID tag is often referred to as a passivedevice because it derives the energy needed for its operation from theinterrogation signal beamed at it. The tag rectifies the field andchanges the reflective characteristics of the tag itself, creating achange in reflectivity that is seen at the interrogator. Thebattery-powered semi-passive RFID tag operates in a similar fashion,modulating its RF cross-section in order to reflect a delta to theinterrogator to develop a communication link. Here, the battery is thesource of the tag's operational power for optional circuitry. Finally,in the active RF tag, a transmitter is used to create its own radiofrequency energy powered by the battery.

[0008] The range of communication for such tags varies according to thetransmission power of the interrogator 12 and the RF tag 14.Battery-powered tags operating at 2,450 MHz have traditionally beenlimited to less than ten meters in range. However, devices withsufficient power can reach up to 200 meters in range, depending on thefrequency and environmental characteristics.

[0009] Security systems have been designed that use RFID devices inproviding restricted access to authorized personnel only, i.e., thosepersonnel or employees authorized to carry a tag. However, a drawback tosuch systems is that tags may be lost or stolen and later used byunauthorized individuals, thus compromising the security. In addition,employees who are no longer authorized to have access or who have beenterminated may continue to use the tag or they may tamper with the tagto obtain information stored therein.

BRIEF SUMMARY OF THE INVENTION

[0010] The disclosed embodiments of the invention are directed to amethod and system for controlling objects, such as RFID tags, andassociated operable objects.

[0011] In one embodiment of the invention, an RFID device is providedthat includes a receiver circuit configured to receive an interrogationsignal and to return a radio frequency signal in response thereto. Thereceiver circuit is further configured to receive a disable signal andto process the disable signal to render the device permanentlyinoperable.

[0012] In another embodiment, a radio frequency identification andcontrol device for tracking and controlling an operable object isprovided. The device is configured to respond to interrogation andcontrol signals from a remote radio frequency identificationinterrogator. In this embodiment of the invention, a receiver circuit isprovided integral with the object and configured to generate returnradio frequency signals in response to the interrogation signals and itis adapted to be coupled to the object to render the object inoperablein response to a disable signal.

[0013] In accordance with another aspect of the foregoing embodiment,the receiver circuit utilizes the operable object as at least a portionof or the entire receiving antenna.

[0014] In accordance with another aspect of the foregoing embodiment,the receiver circuit is configured to enable operation of the object inresponse to an enable signal.

[0015] In accordance with another embodiment of the invention, a methodfor controlling an RFID device is provided. The method includestransmitting a disable signal to the device and receiving and processingthe disable signal to render the device irreversibly non-responsive. Thedevice can be coupled to an operable object, such as a weapon, andconfigured to render the object or weapon operable in response to anenable signal or permanently inoperable in response to a disable signal.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The following detailed description of the embodiments of theinvention will be more readily understood when taken in conjunction withthe following drawings, wherein:

[0017]FIG. 1 is a diagram of an RFID system known in the art;

[0018]FIGS. 2A and 2B are RFID systems utilizing RFID devices inaccordance with the present invention; and

[0019]FIG. 3 is a remote frequency identification and control systemformed in accordance with another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0020] Referring initially to FIG. 2A, shown therein is an RFID system24 comprising an interrogator 26 having an antenna circuit 28 configuredto transmit and receive radio frequency signals to and from an RFIDdevice 30 having an antenna 32. The interrogator 26 includes atransmitter circuit 34 coupled to the antenna 28. The transmitter 34 isconfigured to transmit interrogation signals 35 to the RFID device 30.In addition, the transmitter 34 is configured to generate controlsignals 37 that include a disable signal for reception by the RFIDdevice 30.

[0021] A receiver circuit 36 is coupled to the antenna 32 in the RFIDdevice 30. The antenna 32 may be configured to receive both theinterrogation and control signals, or multiple antennas may be used. Thereceiver circuit 36 is configured in a conventional manner to enable theRFID device 30 to return a radio frequency signal (not shown) inresponse to the interrogation signals 35 from the interrogator 26. Inthis embodiment, the RFID device 30 is a passive RFID tag that utilizesmodulated backscatter reflection of the interrogation signals 35 torespond to the interrogator 26.

[0022] The receiver circuit 36 has associated with it a control circuit33 that is configured to respond to the control signals 37 from theinterrogator 26, which include a disable signal. The disable signal isreceived and processed by the control circuit 33 to render the RFIDdevice 30 permanently inoperable. In this embodiment, the control signalis a modulated signal transmitted at the same frequency as theinterrogation signal.

[0023] Various methods may be used for disabling the device 30. In thedisclosed embodiment, the receiving circuit 36 includes a memory 38, andthe control circuit 33 is configured to alter or erase the memory 38 torender the device 30 irreversibly non-responsive. Alternatively, asshown in FIG. 2B, the receiver circuit 36 can be configured to fuse afusible link 39 in response to the disable signal, such as to ground theantenna 32 or alter its operating characteristics. The receiver circuit36 may be configured to break an electrical conducting link inside theRFID device 30 (not shown) in a manner that is known in the art and willnot be discussed in detail herein.

[0024] In another embodiment of the invention, the receiver circuit 36can be configured to render the antenna 32 or associated antenna circuitinoperable, such as by modifying the operating characteristics. In apassive RFID device, the backscatter or modulation characteristics ofthe antenna circuit can be permanently modified so that the device 30does not respond to further interrogation and control signals.

[0025] Referring next to FIG. 3, shown therein is a radio frequencyidentification and control device 40 for use in tracking and controllingan operable object in response to interrogation signals 52 and controlsignals 50 from a remote RFID interrogator, such as the interrogator 26described above with respect to the embodiment of FIG. 2A. Forillustrative purposes, the object in this embodiment is designated as aweapon 42 having a controller 44 for enabling and disabling operation ofthe weapon 42.

[0026] The RFID device 40 in this embodiment includes an output circuit45 as part of the receiver circuit 46 that is coupled to an antenna 48formed inside the weapon 42. The output circuit 45 is coupled to thecontroller 44, which is configured to control operation of the weapon42. Upon receipt of a control signal 50, the receiver circuit 46 causesthe output circuit 45 to output an enable/disable signal to thecontroller 44. In one embodiment, the control signal 50 comprises adisable signal that is received and processed by the receiver circuit 46and the output circuit 45 to cause the controller 44 to disableoperation of the weapon 42. In another embodiment, the receiver circuit46 and output circuit 45 are configured to receive a control signal 50that causes the controller 44 to enable operation of the weapon 42.Ideally, a control signal line 54 couples the output circuit 45 to thecontroller 44.

[0027] In operation, the receiver circuit 46 is configured to return amodulated radio frequency signal in response to an interrogation signalthat, in one embodiment, identifies the weapon 42 and providesinformation about the location of the weapon. In response to a controlsignal 50 that comprises an enable signal, the receiver circuit 46 andoutput circuit 45 cause the controller 44 to enable operation of theweapon 42. Similarly, in response to a control signal 50 that comprisesa disable signal, the weapon 42 is temporarily or, preferably,permanently disabled.

[0028] The controller 44 in this embodiment is configured to receive thesignal from the control signal line 54 and effectuate the enable/disablecommand through conventional circuitry. This can include, but is notlimited to, known switched, fuses, and devices that perform similarfunctions in response to a control signal.

[0029] Although preferred embodiments of the invention have beenillustrated and described, it is to be understood that various changesmay be made therein. For example, the RFID tag, while disclosed as apassive device (without an independent source of power such as abattery), may be configured as a semi-passive device having a battery tooperate optional accessory circuits. In addition, the disclosedembodiments of the invention can be combined with an active RFID tagdevice, if desired.

[0030] Optionally, the disclosed embodiments of the present inventionmay be combined with applicant's prior invention disclosed in U.S.application Ser. No. 09/589,001 filed on Jun. 6, 2000, entitled “RemoteCommunication System and Method,” which is incorporated herein in itsentirely. The combination of the present invention with a dual frequencyRF tag increases the available power at the tag, and, hence, the rangeof operation.

[0031] More particularly, an interrogator transmits an energy signal ata first frequency that supplies power to the RFID device through a powercircuit in the RFID device. The interrogator transmits interrogationsignals and control signals at a second frequency, or at a second and athird frequency, respectively, which are processed by the RFID device asdescribed herein above.

CLOSURE

[0032] From the foregoing it will be appreciated that, although specificembodiments of the invention have been described herein for purposes ofillustration, various modifications may be made without deviating fromthe spirit and scope of the invention. Accordingly, the invention is notlimited except as by the appended claims.

We claim:
 1. A radio frequency identification (RFID) device, comprising:a receiver circuit configured to receive a radio-frequency interrogationsignal and to return a modulated radio frequency signal bycontinuous-wave backscatter, and a control circuit further configured toreceive a disable signal and to process the disable signal to render theRFID device permanently inoperable.
 2. The device of claim 1, whereinthe receiver circuit is configured to provide passive continuous-wavebackscattering of the interrogation signal and to receive operatingpower from the interrogation signal and the disable signal.
 3. Thedevice of claim 1, wherein the receiver circuit comprises an antennacircuit, and wherein the control circuit is configured to render theantenna circuit inoperable in response to the disable signal.
 4. Thedevice of claim 1, wherein the control circuit is configured to modifythe backscattering characteristics of the antenna circuit in response tothe disable signal.
 5. The device of claim 1, wherein the receivercircuit comprises a memory circuit, and wherein the control circuit isconfigured to permanently alter the memory circuit in response to thedisable signal.
 6. The device of claim 1, wherein the control circuit isconfigured to fuse a fusible link in response to the disable signal. 7.The device of claim 1, wherein the control circuit is configured toirreversibly alter the operating characteristics of the receiver circuitin response to the disable signal.
 8. A radio frequency identification(RFID) system, comprising: an interrogator configured to generate aradio-frequency interrogation signal and a radio-frequency disablesignal; and a passive RFID tag configured to receive the interrogationsignal and to return a modulated radio frequency signal viacontinuous-wave backscatter in response thereto, the RFID tag furthercomprising a control circuit configured to receive the disable signaland to process the disable signal to render the tag permanentlyinoperable.
 9. The system of claim 8, wherein the tag comprises anantenna circuit configured to return the radio frequency signal andwherein the control circuit is configured to render the antenna circuitinoperable in response to the disable signal.
 10. The circuit of claim9, wherein the control circuit is configured to modify the backscattercharacteristics of the antenna circuit in response to the disablesignal.
 11. The system of claim 9, wherein the control circuit isconfigured to irreversibly modify operating characteristics of theantenna circuit in response to the disable signal.
 12. The system ofclaim 9, wherein the receiver circuit comprises a memory circuit, andthe control circuit is configured to permanently alter the memorycircuit in response to the disable signal.
 13. The system of claim 12,wherein the control circuit is configured to erase the memory inresponse to the disable signal.
 14. The system of claim 9, wherein thecontrol circuit is configured to fuse a fusible link in the tag inresponse to the disable signal.
 15. The system of claim 9, wherein thecontrol circuit is configured to break an electrically conductive linein the tag in response to the disable signal.
 16. A method for disablinga radio frequency identification (RFID) device, comprising: transmittinga disable signal to the device; receiving the disable signal at thedevice; and processing the disable signal to render the deviceirreversibly non-responsive.
 17. The method of claim 16, whereinprocessing the disable signal comprises altering a memory in the device.18. The method of claim 17, wherein altering the memory compriseserasing the memory.
 19. The method of claim 16, wherein processing thedisable signal comprises fusing a fusible link in the device.
 20. Themethod of claim 16, wherein processing the disable signal compriseschanging the operating characteristics of the device.
 21. The method ofclaim 16, wherein receiving and processing the disable signal comprisesusing power from the disable signal to render the device irreversiblynon-responsive.
 22. A radio frequency identification and control devicefor tracking and controlling an operable object in response tointerrogation and control signals from a remote radio frequencyidentification (RFID) interrogator, the device comprising: a receivercircuit formed inside the operable object and configured to receive theinterrogation signals and return a modulated radio frequency signal bycontinuous-wave backscatter in response thereto, the receiver circuitadapted to be coupled to the object and to render the object inoperablein response to the disable signal.
 23. The device of claim 22, whereinthe receiver circuit is configured to render the receiver circuit andthe object permanently inoperable in response to the disable signal. 24.The device of claim 23, wherein the receiver circuit is configured toreturn radio frequency signals in response to the interrogation signalsthat comprise data regarding the operational status of the object. 25.The device of claim 22, wherein the receiver circuit is configured toenable operation of the object in response to an enable signal from theremote RFID interrogator.
 26. The device of claim 22, further comprisingthe operable object, and wherein the receiver circuit comprises areceiving antenna that at least a portion of which comprises theoperable object.
 27. The device of claim 22, wherein the receivercircuit comprises a receiving antenna that is formed entirely from theoperable object.
 28. The device of claim 22, wherein the receivercircuit comprises a passive circuit that is powered by the interrogationsignals from the interrogator.
 29. The device of claim 22, wherein thereceiver circuit is battery-powered and comprises an active transmittercircuit.
 30. A radio frequency identification and control system,comprising: a weapon; and a radio frequency identification (RFID) deviceformed internal to the weapon and coupled to the weapon, the RFID deviceconfigured to return a modulated continuous-wave backscattered radiofrequency signal in response to remote interrogation signals and tocontrol operation of the weapon in response to remote control signals.31. The system of claim 30, comprising a remote interrogator configuredto generate the interrogation signals and the control signals and toreceive the return radio-frequency signals.
 32. The system of claim 31,wherein the RFID device is configured to permanently disable the weaponin response to control signals from the interrogator.
 33. The system ofclaim 31, wherein the RFID device is configured to enable operation ofthe weapon in response to control signals from the interrogator.
 34. Thesystem of claim 31, wherein the RFID device is configured to utilize themodulated continuous-wave backscattered radio frequency signals totransmit data regarding operational status of the weapon.
 35. The systemof claim 31, wherein the RFID device is battery powered and isconfigured to transmit signals to the interrogator.